Text and image sharpening of scanned images in the JPEG domain
V. Bhasharan, Konstantinos Konstantinides, Giordano B. Beretta · 2002
The visual quality of scanned color documents suffers because of inherent limitations in color scanners. In cases where the scanned documents will also be compressed using the JPEG standard, we present a new technique that sharpens the compressed images in the DCT domain. Sharpening is achieved by suitably scaling each element of the encoding quantization table to enhance the high-frequency characteristics of the image. Experimental results show improved text and image quality with no additional computation cost.